A cyclic tetrasaccharide, having a structure composed of four glucose molecules bound together via alternating α-1,3-glucosidic linkage and α-1,6-glucosidic linkage, i.e., a compound having a structure of cyclo{→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1-}, represented by Chemical formula 1 (hereinafter, briefly called as “cyclotetrasaccharide”), and a process for producing the saccharide by allowing a hydrolytic enzyme, alternanase, to act on a polysaccharide, alternan, were reported by Gregory L. Cote et al. in European Journal of Biochemistry, Vol. 226, pp. 641-648, 1994. However, the industrial production of cyclotetrasaccharide by the above process has been difficult because of the expensiveness of material alternan. Recently, as disclosed in International Publication Nos. WO 01/90,338 (international application No. PCT/JP01/04,276) and WO 02/10,361 (international application No. PCT/JP01/06,412), applied for by the same applicant as the present invention; a process for producing cyclotetrasaccharide, using both enzymes originated from microorganisms and inexpensive starch as a material, was established. Therefore, the process enables us to produce cyclotetrasaccharide industrially, and the uses of the saccharide are now developing.
Chemical formula 1

In order to extend the uses of cyclotetrasaccharide, it is meaningful to produce novel derivatives of cyclotetrasaccharide, having different physical properties from those of cyclotetrasaccharide. As reports referred to the derivatives of cyclotetrasaccharide, Japanese Patent Application No. 67,282/2001 (title of the invention, “Branched cyclic tetrasaccharide, its preparation and uses”) and U.S. Pat. No. 5,889,179 disclosed the derivative having a structure of glucosyl-cyclotetrasaccharide, i.e., branched cyclotetrasaccharide. Since the derivatives of cyclotetrasaccharide described in those are produced by binding O-glycosyl groups with cyclotetrasaccharide by using O-glycosyl group-transferring enzymes, the resulting derivatives have only O-glycosyl groups. Therefor, it is restricted to change the physical properties of cyclotetrasaccharide by binding an O-glycosyl group(s) with cyclotetrasaccharide.
The object of the present invention is to provide derivatives of cyclotetrasaccharide, having different physical properties from those of cyclotetrasaccharide, compositions comprising the same, and processes for producing the derivatives of cyclotetrasaccharide.